Ballistocardiography (BCG) is getting increasingly prevalent in medical and healthcare service and products primarily due to the advantage of non-invasivencss. Using various types of pressure sensing devices, the body movement of a subject due to his/her cardio activities are captured and converted to digital signals. Then the heart rates or inter-beat intervals can be estimated from the digital signals for monitoring or diagnostic purposes.
However BCG, in contrast to electrocardiography (ECG), is extremely vulnerable to noise or artefacts in the digital signals since the contact of the sensor as well as the body movement of the subject are uncontrolled. Given that the quality of BCG signals is unknown, the key challenge in BCG analysis is to estimate heart beat events with high reliability and sensitivity.
Multi-channel BCG digital signals captured with an array of sensors contains redundant information on cardio activity of a subject and, in theory, can provide more reliable grounds for heart beat event estimation. Existing methods for BCG digital signal analysis tend to use a signal summing or a signal averaging approach for the fusion of multiple channels.
Cepstrum-based methods for signal periodicity estimation are quite established for audio or speech signal analysis, such as for pitch detection. There are also techniques that are proposed to estimate heart beat intervals from cardio signals, such as BCG. However, as heart beats signals are nonstationary, unlike audio signals, heavy constraints have had to be put in those methods when the cepstrum of the signal is computed. One typical constraint is that the duration of the signal window should cover exactly two heart beats, which would require that the heart rate is initially estimated before the cepstrum of the signal can be computed.
Thus, what is needed is a method and system for improved ballistocardiography with a quick and robust signal analysis technique for estimating heart beat rate with high reliability and sensitivity. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the disclosure.